Self-healing concrete trialled by researchers

Scientists from a project led by Cardiff University, have launched a trial of ‘self-healing’ concrete in the South Wales valleys, in an effort to combat potholes and structural damage. This will be the first time the technologies are used in real-world settings. The project aims to create a system that senses damage and repairs it without human intervention, significantly enhancing durability, improving safety and reducing the extremely high maintenance costs spent each year.

In 2014 the estimated cost of returning roads in England and Wales back to a reasonable condition increased to £12 billion. As part of their attempt to reduce this cost, researchers have cast six concrete walls at the test site, each containing different technologies. The site chosen for the trial is Costain’s construction site in Blaenau Gwent, as Costain is one of the major industrial partners on the project.

The first technique is trialling shape-shifting polymers to repair large cracks. These require heating with a small current, to transform into a shape they have previously been taught. It is believed that embedding these into concrete will enable cracks to be closed, or at least minimised.

A second approach involves researchers pumping organic and inorganic healing agents through a network of thin tunnels in the concrete to help fix damage. The final approach utilises tiny capsules embedded into the concrete, containing both bacteria and healing agents. These react when cracks occur, releasing the bacteria that then produce calcium carbonate after accessing nutrients, thereby healing the cracks.

The researchers will load the concrete walls at specific angles to induce cracks and then monitor how effective each of the self-healing techniques is. It is hoped that all three tested technologies will have the ability to detect damage occurring in the concrete structure, and then automatically fix it, and that they can later be integrated into a single system.